Studies in this laboratory over the past several years have shown that the mastication of chow has a profound effect in stimulating the secretory process of the rat parotid gland. Basically, gland components involved in the synthesis of secretory products are affected by increased and decreased mastication: RNA content, rate of synthesis and content of secretory proteins. In many ways the gland changes with enhanced mastication are very similar to several of those induced by chronic isoproterenol treatment. The overall objective of this research proposal is to correlate salivary protein changes to specific cellular organelle changes to provide a better understanding of the relationship of gland function to the secretory process. Three experimental situations will be used in each of the studies: reduced mastication (feeding a liquified chow), enhanced mastication (feeding a "bulk" chow containing non-nutritive cellulose), and enhanced stimulation by chronic isoproterenol treatment. Cannulated parotid saliva will be collected and examined for protein content by acrylamide gel electrophoresis and for changes in the specific activities of several secretory enzymes. Total gland RNA will be determined, ribosomes will be isolated and the percentage of RNA in ribosomes as well as the percentage of active ribosomes determined. Secretory granules will be isolated and their physical and biochemical characteristics determined by density gradient centrifugation, and their contents studied by acrylamide gel electrophoresis, as well as kinetics of protein release as affected by hypotonicity, pH and CaC12 concentration. Since nuclear ploidy has been shown to exist with chronic isoproterenol treatment and since studies with enhanced mastication have indicated that gland DNA is increased, total gland DNA, DNA per nucleus, mitotic activity, thymidine uptake and percentage of labeled nuclei will be determined.